Abstract
This paper provides an explicit polynomial rate of asymptotic regularity for (in general inconsistent) feasibility problems in Hilbert space. In particular, we give a quantitative version of Bauschke’s solution of the zero displacement problem as well as of various generalizations of this problem. The results in this paper have been obtained by applying a general proof-theoretic method for the extraction of effective bounds from proofs due to the author (‘proof mining’) to Bauschke’s proof.
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J. Avigad and J. Iovino. Ultraproducts and metastability. New York J. Math. 19: 713–727, 2013.
J. Baillon, and R.E. Bruck. The rate of asymptotic regularity is \(O(1/n)\) [\(O/\sqrt{n}\)], in: Theory and applications of nonlinear operators of accretive and monotone type, pp. 51–81, Dekker, 1996.
H.H. Bauschke. The composition of projections onto closed convex sets in Hilbert space is asymptotically regular. Proc. Amer. Math. Soc. 131: 141–146, 2003.
H.H. Bauschke, J.M. Borwein, and A.S. Lewis. The method of cyclic projections for closed convex sets in Hilbert space. In: Recent developments in optimization theory and nonlinear analysis (Jerusalem 1995), pp. 1–38, Amer. Math. Soc., Providence, RI, 1997.
H.H. Bauschke, V. Martín-Márquez, S.M. Moffat, and X. Wang (2012) Compositions and convex combinations of asymptotically regular firmly nonexpansive mappings are also asymptotically regular. Fixed Point Theory and Applications 2012: 52, 11 pp., https://doi.org/10.1186/1687-1812-2012-53.
H. Brezis and A. Haraux. Image d’une somme d’operateurs monotones et applications. Israel Journal of Mathematics 23: 165–186, 1976.
F.E. Browder. Convergence theorems for sequences of nonlinear operators in Banach spaces. Math. Zeitschrift 100: 201–225, 1967.
F.E. Browder and W.V. Petryshyn. The solution by iteration of nonlinear functional equations in Banach spaces. Bull. Amer. Math. Soc. 72: 571–575, 1966.
R.E. Bruck. A simple proof that the rate of asymptotic regularity of \((I+T)/2\) is \(O(1/\sqrt{n}\)), in: Recent advances on metric fixed point theory (Seville, 1995), pp. 11–18, 1996.
R.E. Bruck and S. Reich. Nonexpansive projections and resolvents of accretive operators in Banach spaces. Houston J. Math. 3: 459–470, 1977.
S. Cho. A variant of continuous logic and applications to fixed point theory. Preprint 2016, arXiv:1610.05397.
P. Gerhardy and U. Kohlenbach. General logical metatheorems for functional analysis. Trans. Amer. Math. Soc. 360: 2615–2660, 2008.
K. Goebel and S. Reich. Uniform Convexity, Hyperbolic Geometry, and Nonexpansive Mappings, Marcel Dekker, New York, 1984.
D. Günzel. Logical metatheorems in the context of families of abstract metric structures. Master-Thesis, TU Darmstadt. 2013.
M.A.A. Khan and U. Kohlenbach. Quantitative image recovery theorems. Nonlinear Anal. 106: 138–150, 2014.
U. Kohlenbach. Some logical metatheorems with applications in functional analysis. Trans. Amer. Math. Soc. 357: 89–128, 2005.
U. Kohlenbach. Applied Proof Theory: Proof Interpretations and their Use in Mathematics. Springer Monographs in Mathematics. xx+536pp., Springer Heidelberg-Berlin, 2008.
U. Kohlenbach. On the quantitative asymptotic behavior of strongly nonexpansive mappings in Banach and geodesic spaces. Israel Journal of Mathematics 216: 215–246, 2016.
S. Reich. Asymptotic behavior of contractions in Banach spaces. J. Math. Anal. Appl. 44: 57–70, 1973.
S. Reich. The range of sums of accretive and monotone operators. J. Math. Anal. Appl. 68: 310–317, 1979.
S. Reich. A limit theorem for projections, Linear and Multilinear Algebra 13: 281–290, 1983.
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Communicated by James Renega.
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Kohlenbach, U. A Polynomial Rate of Asymptotic Regularity for Compositions of Projections in Hilbert Space. Found Comput Math 19, 83–99 (2019). https://doi.org/10.1007/s10208-018-9377-0
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DOI: https://doi.org/10.1007/s10208-018-9377-0